﻿/* Copyright (C) 2011 by John Cronin
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:

 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.CompilerServices;

namespace tysos
{
    class Unwind
    {
        ulong cur_rbp;

        public Unwind()
        {
            cur_rbp = ABI.OtherOperations.GetRBP();

            // discard the current stack frame (i.e. that in the Unwind constructor itself)
            UnwindOne();
        }

        public unsafe ulong UnwindOne()
        {
            ulong next_rbp = *((ulong*)cur_rbp);
            ulong rip = *((ulong*)(cur_rbp + 8));
            cur_rbp = next_rbp;
            return rip;
        }

        public unsafe ulong UnwindOneWithErrorCode()
        {
            ulong next_tbp = *((ulong*)cur_rbp);
            ulong rip = *((ulong*)(cur_rbp + 16));
            cur_rbp = next_tbp;
            return rip;
        }
    }
}
